Funding ceased, as Principal Investigator is no longer based at the Bionics Institute (Sponsor).

This is a single-group clinical trial to evaluate the performance of the EarGenie minimum viable product (MVP) in normal hearing infants. The EarGenie MVP tests for detection and discrimination of sounds will be administered, and the sensitivity and specificity of the tests will be estimated for a range of sound levels (detection) and speech sound contrasts (discrimination).

Procedures:

All procedures will be carried out in a single test session.

Determination of infant eligibility will be undertaken by confirming that the infant has passed hearing screening or diagnostic audiological assessment and is under the age of 2 years.

Before completing the fNIRS tests, the infant will undergo otoscopy and tympanometry to exclude possible temporary conductive hearing loss associated with abnormal tympanometric results. These are standard audiological procedures. If the infant has abnormal tympanometric results in both ears on the day, the test session will be rescheduled. The parent/guardian will be advised of the finding and its possible consequences (possible conductive hearing loss, possible progression to acute otitis media) and advised to seek medical advice should the infant show signs of illness or if hearing loss is suspected.

All assessments in the fNIRS test session will be undertaken by qualified paediatric audiologists who are trained in the fNIRS procedures.

For the fNIRS tests, the infant will be asleep or in a quietly entertained response state.

After the headgear is placed on the infant's head, an optode calibration procedure is undertaken to ensure the equipment is ready. During the actual test, blocks of speech sounds lasting 5.4 seconds will be played to the infant either via tubephone or via speakers. During and after the test session, the infant will be monitored for any signs of discomfort or distress. Testing will discontinue if the infant is not either asleep or in a quiet response state.

For the detection test, a single speech sound "BA" will be presented at several levels (35, 50, and 65 dBSPL), and the test blocks will include "no sound" blocks to allow estimates of false positive results.

For the discrimination test, three different speech contrasts will be presented ("BA/TEA", "BA/BEE", and "BA/GA") at 65 dB SPL. The test will also include blocks of "BA/BA" to allow estimates of false positive rates.

For each infant, the sound levels at which "BA" evoked a statistically significant response will be recorded, and/or the speech contrasts which evoked a significant discrimination response will be recorded. Each infant will either have a detection test or a discrimination test, or both if their response state allows. At least 50 full detection and 50 full discrimination test results for estimating sensitivity and specificity outcome measures will be obtained.

Inclusion Criteria:

Each infant must meet all of the following criteria to be enrolled in this trial:

• Is between the ages of 1 and 24 months at the time of fNIRS testing.
• Has no known hearing loss, having either passed newborn hearing screening or diagnostic audiological assessment.
• Has a legally acceptable representative capable of understanding the informed consent document and providing consent on the participant's behalf.

Exclusion Criteria:

• Infants with skin conditions such as cradle cap, eczema, or other skin conditions on the head will be excluded.

There are no additional exclusion criteria other than not meeting the inclusion criteria.